TECHNICAL FIELD
[0001] This invention relates to homogeneous, general purpose, heavy-duty liquid laundry
detergent compositions containing a mixture of anionic and nonionic synthetic detergents,
fatty acid soap, polycarboxylate builder, solvent and water. Improved odor and safety
are obtained by omitting C
1-C
6 monohydric alcohols which have been used in prior art compositions of this particular
type, and using polyols exclusively for the solvent.
BACKGROUND ART
[0002] Bogardus, U.S. Patent No. 3,761,420 issued September 25, 1973, and Landwerlen et
al, U.S. Patent No. 3,860,536 issued January 14, 1975 disclosed liquid, enzyme- based,
stain removal compositions intended primarily as laundry additives for spotting and
soaking, In both patents, solutions of water and lower polyols were used to preserve
enzymatic activity. Bogardus optionally used glassy phosphate as a chelating agent,
while Landwerlen et al included anionic and/or nonionic surfactants and optionally
solvents such as naphtha and other laundry additives to improve the removal of oil
and grease stains in addition to the protein and carbohydrate stains removed by proteolytic
and amylolytic enzyme, respectively.
[0003] Heavy duty liquids containing some or all of the ingredients recited in the preceding
section have been the subject of prior art references. Barrat et al, U.S. Patent No.
4,285,841 issued August 25, 1981, related to general purpose, heavy duty laundry liquids
containing a mixture of anionic and nonionic synthetic detergents and fatty acid soap,
and phase regulant selected from among lower alphatic alcohols having 2-6 carbon atoms
and 1-3 hydroxyl groups, esters of diethylene glycol, lower alphatic monoalcohols
having 1-4 carbon atoms, detergent hydrotropes such as sodium toluene sulfonate, and
water. All examples contained 5-10% ethanol. The objective of the invention was to
secure superior textile cleaning through use of highly concentrated compositions,
stablized by phase regulant. Odor was not mentioned.
[0004] Tolfo et al, U.S. Patent No. 4,287,082 issued September 1, 1981, disclosed similar
compositions which additionally contained enzyme, enzyme-accessible calcium, and short
chain carboxylic acid such as formic acid. Detergency was improved due to the presence
of stabilized enzyme. Examples contained 10-12% ethanol. Odor was not mentioned.
[0005] Wertz et al, European Patent Publication No. 0095205 dated November 30, 1983, disclosed
liquid compositions containing anionic surfactant, nitrogen containing surfactant
such as quaternary ammonium or amine or amine oxide surfactant, and fatty acid soap.
The phase regulant mentioned as an optional component comprised, in the examples,
mixtures of ethanol (1% minimum) and 1, 2-propane diol. The only mention of odor was
in connection with order of addition of the components, and here the preferred product
was referred to as having a "less objectionable" base odor.
[0006] Hughes, U.S. Patent N° 4.5D7.219, issued March 26, 1985 was directed to compositions
comprising combinations of sulfonate, alcohol ethoxylate sulfate, and ethoxylated
nonionic surfactants; fatty acid; polycarboxylate builder; and a solvent system comprised
of 2-10% ethanol, 2-15% lower polyol preferably propylene glycol, and water. Preferred
compositions also included a quaternary ammonium or amine or amine oxide surfactant,
and an alkanolamine in the amount of 0-0.04 mols per 100 gm. of composition.
[0007] Exemplified compositions Included 4.0-8.5% ethanol. Detergency, phase stability and
bleach stability were the stated objectives of the invention. It was noted that while
low levels of monoethanolamine were preferred to enhance product stability, detergency
performance and odor, the amount should be minimized for best chlorine bleach com-
patability.
SUMMARIZED DISCLOSURE OF THE INVENTION
[0008] This invention is a homogeneous liquid laundry detergent composition, substantially
free from C
1-C
6 monohydric alcohols, which comprises by weight of the composition:
(a) non-soap anionic surfactant in an amount from about 8% to about 33% on a surfactant
acid basis;
(b) C10-C14 fatty acid soap in an amount from about 4% to about 20% on a fatty acid basis;
(c) ethoxylated nonionic surfactant in an amount from about 1% to about 15%;
(d) water-soluble polycarboxylate builder in an amount from about 1% to about 8% on
a builder acid basis;
(e) neutralizing agent, selected from the group consisting of alkali metal hydroxides
and at least about 2% alkanolamines, in a total amount sufficient to produce a pH
for the composition of from about 7 to about 9 when measured as a 10 wt. % solution
at 20°C.;
(f) enzyme selected from the group consisting of protease and amylase in an amount
from about 0.05% to about 2%;
(g) aliphatic polyol having from 2 to 6 carbon atoms and from 2 to 4 hydroxyl groups
in an amount from about 4% to about 25%;
(h) water in an amount from about 20% to about 70%; and
wherein the sum of components (a), (b) and (c) is not greater than about 55%.
[0009] Especially preferred compositions include the following:
(1) The non-soap anionic surfactant is a mixture of (i) alkyl benzene sulfonate in
which the alkyl group contains from about 9 to about 15 carbon atoms in straight or
branched chain configuration and (ii) alkyl polyethoxy ether sulfate surfactant having
an average of about 1 to about 6 -CH2CH20- groups per molecule and in which the alkyl group contains 10 to 16 carbon atoms.
(2) The ethoxylated nonionic surfactant is the condensation product of 4 to 8 mols
of ethylene oxide with 1 mot of straight or branched chain, primary or secondary alphatic
alcohol having from 12 to 14 carbon atoms.
(3) The neutralizing agent includes from about 4% to about 12% monoethanolamine.
(4) The polycarboxylate builder is citric acid.
(5) The polyol is 1,2-propane diol (propylene glycol).
DETAILED DESCRIPTION OF THE INVENTION
[0010] In the paragraphs which follow, a description of each of the components of this invention
is given seriatim. The problems to which this invention is directed, and their solutions,
are described in the discussion hereinafter of Component (g)-Polyol Solvent.
Component (a). Non-Soap Anionic Surfactant.
[0011] The detergent compositions herein contain from about 8% to about 33%, preferably
from about 12% to about 25%, of non-soap anionic surfactant, expressed on a surfactant
acid basis.
[0012] Preferred anionic non-soap surfactants are water soluble salts of alkyl benzene sulfonate,
alkyl sulfate, alkyl polyethoxy ether sulfate, paraffin sulfonate, alpha-olefin sulfonate,
alpha-sulfocarboxylates and their esters, alkyl glyceryl ether sulfonate, fatty acid
monoglyceride sulfates and sulfonates, alkyl phenol polyethoxy ether sulfate, 2-acyloxy-alkane-I-sulfonate,
and beta-alkyloxy alkane sulfonate.
[0013] Especially preferred alkyl benzene sulfonates have about 9 to about 15 carbon atoms
in a linear or branched alkyl chain, more especially about 11 to about 13 carbon atoms.
Especially preferred alkyl sulfate has about 8 to about 22 carbon atoms in the alkyl
chain, more especially from about 12 to about 18 carbon atoms. Especially preferred
alkyl polyethoxy ether sulfate has about 10 to about 18 carbon atoms in the alkyl
chain and has an average of about 0.5 to about 12 -CH
2CH
20- groups per molecule, especially about 10 to about 16 carbon atoms in the alkyl
chain and an average of about 1 to about 6 -CH
2CH
20- groups per molecule.
[0014] Especially preferred paraffin sulfonates are essentially linear and contain from
about 8 to about 24 carbon atoms in the alkyl chain, more especially from about 14
to about 18 carbon atoms. Especially preferred alpha-olefin sulfonate has about 10
to about 24 carbon atoms in the alkyl chain, more especially about 14 to about 16
carbon atoms; alpha-olefin sulfonates can be made by reaction with sulfur trioxide
followed by neutralization under conditions such that any sultones present are hydrolyzed
to the corresponding hydroxy alkane sulfonates. Especially preferred alpha-sulfocarboxylates
contain from about 6 to about 20 carbon atoms in the alkyl chain; included herein
are not only the salts of alpha-sulfonated fatty acids but also their esters made
from alcohols containing about 1 to about 14 carbon atoms.
[0015] Especially preferred alkyl glyceryl ether sulfonates are ethers of alcohols having
about 10 to about 18 carbon atoms in the alkyl chain, more especially those derived
from coconut oil and tallow. Especially preferred fatty acid monoglyceride sulfates
and sulfonates have about 10 to about 18 carbon atoms in the alkyl chain. Especially
preferred alkyl phenol polyethoxy ether sulfate has about 8 to about 12 carbon atoms
in the alkyl chain and an average of about 1 to about 10 -CH
2CH
20- groups per molecule. Especially preferred 2-acyloxyalkane-l-sulfonates contain
from about 2 to about 9 carbon atoms in the aryl group and about 9 to about 23 carbon
atoms in the alkane moiety. Especially preferred betaalkyloxy alkane sulfonate contains
about 1 to about 3 carbon atoms in the alkyl group and about 8 to about 20 carbon
atoms in the alkane moiety.
[0016] The alkyl chains of the foregoing non-soap anionic surfactants can be derived from
natural sources such as coconut oil or tallow, or can be made synthetically as for
example using the Ziegler or Oxo processes. Water solubility can be achieved by using
alkali metal or alkanolammonium cations.
[0017] Mixtures of non-soap anionic surfactants are especially preferred. One particularly
preferred mixture comprises an anionic sulfonate surfactant containing a
C9-
C15 alkyl or alkenyl group, more particularly salts of alkylbenzene sulfonates in which
the alkyl group contains from about 9 to about 15 carbon atoms in straight or branched
chain configuration, most particularly C
11-C
13 linear alkylbenzene sulfonate; mixed with a C
10-C
16 alkyl or hydroxyalkyl polyethoxy ether sulfate surfactant having an average of about
1 to about 6 -CH
2CH
20- groups per molecule, more particularly a C12-C15 alkyl polyethoxy ether sulfate
having an average of about 1 to about 3 -CH
2CH
20- groups per molecule.
[0018] Preferred proportions of these mixtures are comprised of anionic sulfonate surfactant
and polyethoxy ether sulfate surfactant in weight ratios from about 1:4 to about 4:1,
more preferably from about 1:2.5 to about 1.5:1.
Component (b). Fatty Acid Soap.
[0019] The detergent compositions herein contain fatty acid soap. It is convenient, however,
to express the composition in terms of the fatty acid moiety thereof. It will be understood
that compositions at the pH of this invention (about 7.0-9.0) contain a mixture of
the free fatty acid species and the neutralized soap species.
[0020] The fatty acid moiety of the soaps of this invention is a saturated fatty acid containing
from about 10 to about 14 carbon atoms. The weight ratio of C
10-12 fatty acid to C
14 fatty acid is preferably at least about 1:1, more preferably at least about 1.5:1.
Soaps can be made by direct saponification of natural fats and oils such as coconut
oil and palm kernel oil, or by the neutralization of free fatty acids obtained from
either natural or synthetic sources. Preferred are coconut fatty acids; palm kernel
fatty acids; and mixtures of lauric and myristic acid in weight ratio from about 1:1
to about 5:1. Oleic acid may be added in minor amount, i.e. up to about 50% of the
total fatty acid, and when so used is considered to be a part of component (b).
[0021] The amount of fatty acid soap in the compositions of this invention, expressed on
a fatty acid basis, is from about 4% to about 20%, preferably from about 6% to about
15%.
[0022] Component (c). Ethoxylated Nonionic Surfactant.
[0023] Preferred nonionic surfactants are water soluble compounds produced by the condensation
of ethylene oxide with a hydrophobic compound such as an alcohol, alkyl phenol, polypropoxy
glycol, or polypropoxy ethylene diamine.
[0024] Especially preferred polyethoxy alcohols are the condensation products of about 3
to about 9 mols of ethylene oxide with 1 mol of branched or straight chain, primary
or secondary aliphatic alcohol having from about 10 to about 16 carbon atoms; more
especially about 4 to about 8 mols of ethylene oxide condensed with 1 mol of straight
or branched chain, primary or secondary aliphatic alcohol having from about 12 to
about 14 carbon atoms. Certain species of polyethoxy alcohols are commercially available
from the Shell Chemical Company under the trade name "Neodol" .
[0025] Especially preferred polyethoxy alkyl phenols are the condensation products of about
3 to about 9 mols of ethylene oxide with 1 mol of alkyl phenol having a branched or
straight chain alkyl group containing about 8 to about 12 carbon atoms. Certain species
of polyethoxy alkyl phenols are commercially available from the GAF Corporation under
the trade name "lgepal".
[0026] Especially preferred polyethoxy polypropoxy glycols are commercially available from
BASF-Wyandotte under the trade name "Pluronic". Especially preferred condensates of
ethylene oxide with the reaction product of propylene oxide and ethylene diamine are
commercially available from BASF-Wyandotte under the trade name "Tetronic".
[0027] Particularly preferred ethoxylated nonionic surfactants are condensation products
of about 6.5 mols of ethylene oxide with 1 mol of C
12-C
13 straight chain primary or secondary aliphatic alcohol.
[0028] Ethoxylated nonionic surfactants are used in amounts from 1% to about 15%, preferably
from about 2% to about 10%, more preferably from about 4% to about 8%, by weight of
the composition. The weight ratio of ethoxylated nonionic surfactant to non-soap anionic
surfactant is preferably from about 1:10 to about 1:1, more preferably from about
1 : to about 1:2.
[0029] The ethoxylated nonionic surfactants of this invention preferably have an HLB (hydrophilic/lipophilic
balance) of from about 10 to about 13.
[0030] The sum of components (a), (b) and (c) of this invention is not greater than about
55%, preferably not greater than about 45%, by weight of the composition.
[0031] Component (d). Polycarboxylate Builder.
[0032] Another essential component of the compositions of this invention is polycarboxylate
detergent builder. The various aminopolycarboxylates, cycloalkane polycarboxylates,
ether polycarboxylates, alkyl polycarboxylates, epoxy polycarboxylates, tetrahydrofuran
polycarboxylates, benzene polycarboxylates, and polyacetal polycarboxylates are suitable
for use herein.
[0033] Examples of such polycarboxylate builders are the water-soluble salts of mellitic
acid, citric acid, pyromellitic acid, benzene pentacarboxylic acid, oxydiacetic acid,
car- boxymethyloxysuccinic acid, carboxymethyloxymalonic acid, cis-cyclohexanehexacarboxylic
acid, cis- cyclopentanetetracarboxylic acid, oxydisuccinic acid, ethylenediaminetetraacetic
acid; nitrilotriacetic acid; and phytic acid. Polycarboxylate builders are described
in Leikhim et al, U.S. Patent No. 4,284,532 issued August 18, 1981; Eckey, U.S. Patent
No. 1,739,942 issued March 27, 1956; Diehl, U.S. Patent No. 3,308,067 issued March
7, 1967; and Crutchfield et al, U.S. Patent Nos. 4,144,226 issued March 13, 1979 and
4,146,495 issued March 27, 1979; all of which are hereby incorporated herein by reference.
[0034] Useful polycarboxylate detergent builders also include the water-soluble salts of
polymeric aliphatic polycarboxylic acids having the following structural and physical
characteristics: (a) a minimum molecular weight of about 350 calculated as to the
acid form; (b) an equivalent weight of about 50 to about 80 calculated as to acid
form; (3) at least 45 mol percent of the monomeric species having at least two carboxyl
radicals separated from each other by not more than two carbon atoms; (d) the site
of attachment of the polymer chain of any carboxyl-containing radical being separated
by not more than three carbon atoms along the polymer chain from the site of attachment
of the next carboxyl-containing radical. Specific examples of such builders are the
polymers and copolymers of itaconic acid, aconitic acid, maleic acid, mesaconic acid,
fumaric acid, methylene malonic acid, and citraconic acid.
[0035] Citric acid is a preferred polycarboxylate builder.
[0036] The compositions of this invention contain from about 1% to about 8%, preferably
from about 2% to about 6%, of polycarboxylate detergent builder.
Component (e). Neutralization Agent.
[0037] The compositions of this invention have a pH of about 7 to about 9 when measured
as a 10 wt.% solution at 20°C. This is achieved by adding appropriate amounts of one
or more bases to the portions of the composition that may be obtained in their acidic
form: sulfonic and/or sulfuric detergent acids, fatty acid, polycarboxylate builder
acid, and perhaps certain minor ingredients. These bases are comprised of alkali metal
hydroxides, alkanolamines, and mixtures thereof, preferably selected from among sodium
and potassium hydroxides and mono-, di-, and tri-ethanolamines.
[0038] Good solubilization and pnase stabilization are achieved by using at least about
2% alkanolamine by weight of the composition. Preferred usage is from about 2% to
about 18% alkanolamine, more preferably from about 4% to about 12% monoethanolamine,
by weight of the composition.
[0039] As is well known, higher concentrations of the solid components of the composition
or achievement of greater physical stability for the homogeneity of the composition
tend to require relatively more potassium and less sodium. Accordingly, when alkali
metal hydroxides are used in such circumstances, the molar ratio of sodium to potassium
in the finished composition is preferably from about 1:10 to about 4:3, more preferably
from about 3:5 to about 1 :1 .
Component (f). Enzyme.
[0040] The compositions of this invention contain enzymes in an amount of from about 0.05%
to about 2%, preferably from about 0.1% to about 1.5%. Protease, amylase, or mixtures
thereof can be used.
[0041] Preferred proteolytic enzymes provide a proteolytic activity of at least about 5
Anson Units (about 1,000,000 Delft Units) per liter of liquid detergent composition,
preferably from about 10 to about 40 Anson Units. Suitable proteolytic enzymes include
the many species known to be adapted for use in detergent compositions. Commercial
enzyme preparations such as "Alcalase" sold by Novo Industries A/S, Copenhagen, Denmark,
and "Maxatase" sold by Gist-Brocades, Delft, The Netherlands, are suitable. Other
preferred proteolytic enzyme compositions include those commercially available under
the tradenames SP-72 ("Esperase") manufactured and sold by Novo Industries and "AZ-Protease"
manufactured and sold by Gist-Brocades. A more complete disclosure of suitable proteolytic
enzymes can be found in U.S. Patent 4,101,457, Place et al, issued July 18, 1978,
incorporated herein by reference.
[0042] Alpha-amylases are also suitable for use in the compositions of this invention. They
are used in amounts comparable with protease usage. When both protease and amylase
are used, their weight ratio is preferably from about 30:1 to about 3:1. Suitable
amylases include "Rapidase" sold by Gist-Brocades and "Termamyl" sold by Novo Industries.
More complete disclosures of suitable amylases are given in U.S. Patent 3,790,482,
Jones et al, issued February 5, 1974, and EPO publication 0118933, Severson, published
September 19, 1984, both incorporated herein by reference.
Component (g). Polyol Solvent.
[0043] When added to the compositions described herein, monohydric alcohols have been found
to cause malodors that are distinctly noticeable whether or not perfume is present.
Monohydric alcohols are highly volatile, with boiling points in °C. ranging from 65
for methanol to 78 for ethanol to 97 for n-propanol to 156 for n-hexanol, with branched
chain alcohols boiling lower than the n-alcohols for each series of homologs. It is
believed that these malodors result from two causes: first, the sharp intrinsic odor
of these volatile compounds per se; and secondly, and more importantly, the propensity
of these volatile compounds to lift up and carry the odors of other portions of the
composition that may be unpleasant. The alkanolamines, including mono-,di- and tri-ethanolamine,
are major sources of malodors. Enzymes are other important sources. To a lesser extent,
but still noticeable, are malodors arising from fatty acids and the impurities and
side reaction products present in commercially available surfactant raw materials.
[0044] It is well known that malodors of this kind, even in a perfumed product, and even
though they do not affect detergency or other performance characteristics, can exert
a strong influence on potential customers in the marketplace. Indeed, the economic
importance of good product odor can hardly be overstated.
[0045] Accordingly, the compositions of this invention are substantially free of C
1-C
6 mohohydric alcohols. -By substantially free is meant that no more than a trace is
present; i.e., no more than a fractional percentage such as may for example be brought
in as impurity in one or more raw materials of the composition.
[0046] The solvents which comprise component (f) of the compositions of this invention are
aliphatic polyols having from 2 to 6, preferably from 2 to 4, carbon atoms; and from
2 to 4, preferably 2 or 3, hydroxyl groups. Specific solvents utilizable in this invention
are ethylene glycol, propylene glycol (1,2-propane diol), trimethylene glycol, diethylene
glycol, hexylene glycol and glycerine. 1,2-propane diol is a preferred solvent. Its
boiling point is 189°C. and all other polyols specifically mentioned above boil at
even higher temperatures. Even the lowest boiling polyol within the scope of this
invention boils within a few degrees of the temperature cited above.
[0047] These polyols are used in the composition in amounts of from about 4% to about 25%,
preferably from about 7% to about 20%, most preferably from about 9% to about 14%
by weight of the composition.
[0048] Another advantage contributed by the polyols, through their lower volatility, is
safety. It is common knowledge that a manufacturing facility handling any of the lower
alcohols must be carefully (and expensively) designed, constructed, maintained and
operated to be safe from fire and explosion. Furthermore, finished liquid detergent
compositions containing significant amounts of the lower alcohols have relatively
low flash points. Closed cup flash points of comparable samples are raised about 30°C.
when the solvent is switched from an ethanol/polyol mixture of the prior art to an
all-polyol system. This is a meaningful contribution to safety in manufacturing, in
warehousing, in shipping (especially by air where flashpoint regulations are strict),
on the grocery store shelf, and in consumers' homes.
Component (h). Water.
[0049] Component (h) of the composition of this invention is water, which is used an amount
from about 20% to about 70%, preferably from about 28% to about 50%, by weight of
the composition.
[0050] The compositions of this invention, using mixtures of polyols and water for stabilization,
are homogeneous, isotropic solutions at room temperature. Within the ranges of usage
identified herein, it is within the capability of a person of ordinary skill in the
art to adjust percentages of the various components to improve phase stability at
elevated or reduced temperatures or during freeze/thaw cycles, or to maintain a fixed
degree of phase stability while diluting the formula to reduce cost or concentrating
it to improve performance.
Optional Components.
[0051] Cosurfactant. In addition to the surfactants which constitute elements (a), (b) and
(c) of this invention, a cosurfactant selected from certain quaternary ammonium, amine
and amine oxide surfactants can optionally be used at levels from about 0.5% to about
5%, preferably from about 1% to about 3%, by weight of the composition.
[0052] The quaternary ammonium surfactants useful herein are of the formula:
wherein R
2 is an alkyl or alkyl benzyl group having from about 6 to about 16 carbon atoms in
the alkyl chain; each R
3 is selected from the group consisting of -CH
2CH
2-, -CH
2CH(CH
3)-, -CH
2CH(CH
2OH)-, -CH
2CH
2CH
2-, and mixtures thereof; each R is selected from the group consisting of C
1-C
4 alkyl, C
1-C
4 hydroxyalkyl, benzyl, and hydrogen when y is not 0; R is the same as R
4 or is an alkyl chain wherein the total number of carbon atoms of R plus R is from
about 8 to about 16; each y is from 0 to about 10 and the sum of the y values is from
0 to about 15; and X is any compatible anion.
[0053] Preferred of the above are the alkyl quaternary ammonium surfactants, especially
the mono-long chain alkyl surfactants described in the above formula when R is selected
from the same groups as R
4. The most preferred quaternary ammonium surfactants are the chloride, bromide and
methylsulfate C
8-16 alkyl trimethylammonium salts, C
8-16 alkyl di(hydroxyethyl)methylammonium salts, the C
8-16 alkyl hydroxyethyldimethylammonium salts, C
8-16 alkyloxypropyl trimethylammonium salts, and the C
8-16 alkyloxypropyl dihydroxyethylmethylammonium salts. Of the above, the C
10- C
14 alkyl trimethylammonium salts are preferred, e.g., decyl trimethylammonium methylsulfate,
lauryl trimethylammonium chloride,myristyltrimethylammonium bromide and coconut trimethylammonium
chloride and methylsulfate.
[0054] Under cool water washing conditions, i.e., less than about 20°C., the C
8-10 alkyl trimethylammonium surfactants are particularly preferred since they have lower
Krafft boundaries and crystallization temperatures than the longer chain quaternary
ammonium surfactants.
[0055] Amine surfactants useful herein are of the formula:
2 3
wherein the R
2, R
3, R
4, R and y substituents are as defined above for the quaternary ammonium surfactants.
Particularly preferred are the C
12-16 alkyl dimethyl amines.
[0056] Amine oxide surfactants useful herein are of the formula:
wherein the R , R , R
4, R and y substituents are also as defined above for the quaternary ammonium surfactants.
Particularly preferred are the C
12-16 alkyl dimethyl amine oxides.
[0057] Enzyme Stabilizer. Enzymes are desirably stabilized by using a mixture of a short
chain carboxylic acid salt and calcium ion, such as disclosed in U.S. Patent 4,318,818,
Letton et al, issued March. 9, 1982, incorporated herein by reference.
[0058] The short chain carboxylic acid salt is preferably water-soluble and most preferably
is a formate, e.g., sodium formate. The short chain carboxylic acid salt is used at
a level from about 0.25% to about 10%, preferably from about 0.3% to about 3%, more
preferably from about 0.5% to about 1.5% by weight of the composition. Any water-soluble
calcium salt can be used as a source of calcium ion, including calcium acetate, calcium
formate and calcium propionate. The composition should contain from about 0.1 to about
30 millimols of calcium ion per liter, preferably from about 0.5 to about 15 millimols
of calcium ion per liter. When materials are present which complex calcium ion, it
is necessary to use high levels of calcium ion so that there is always some minimum
level available for the enzyme.
[0059] Protease is preferably stabilized in the present compositions by the addition of
from about 0.25% to about 10%, more preferably from about 0.5% to about 5%, most preferably
from about 0.75% to about 3%, by weight of boric acid or a compound capable of forming
boric acid in the composition (calculated on the basis of the boric acid). Boric acid
is preferred, although other compounds such as boric oxide, borax and other alkali
metal berates (e.g., sodium ortho-, meta- and pyroborate, and sodium pentaborate)
are suitable. Substituted boric acids, Ce.g., phenylboronic acid, butane boronic acid,
and n-bromo phenylboronic acid) can also be used in place of boric acid. Boric acid
type enzyme stabilizers are described more fully in Severson, U.S. Patents 4.537.706
and 4.537.707, both issued on August 27, 1985, and incorporated herein by reference.
[0060] Other Optional Components for use in the liquid detergents herein include polyacids,
soil removal agents, antiredeposition agents, suds regulants, hydrotropes, opacifiers,
antioxidants, bactericides, dyes, perfumes, and brighteners as described in U.S. Patent
4,285,841, Barrat et al, issued August 25, 1981, incorporated herein by reference.
Such optional components generally represent less than about 15%, preferably from
about 2% to about 10%, by weight of the composition.
[0061] Preferred compositions contain from about 0.01% to about 1% of a polyacid or salt
thereof to enhance pretreatment performance. Preferred polyacids for use herein are
ethylenediamine tetramethylenephosphonic acid, diethylene triamine pentamethylenephosphonic
acid, and diethylenetriamine pentaacetic acid, or the salts thereof. These polyacids/salts
are preferably used in an amount from about 0.1% to about 0.8%.
[0062] Preferred compositions also contain from about 0.5% to about 3%, preferably from
about 1% to about 2%, by weight of the composition of a highly ethoxylated polyethyleneamine
or polyethyleneimine soil removal and antiredeposition agent.
[0063] A particularly preferred material is tetraethylene pentaimine ethoxylated with about
15-18 mols of ethylene oxide at each hydrogen site.
[0064] A preferred suds regulant is the siliconelsilica mixture disclosed in Bartolotta
et al, U.S. Patent No. 3,933,672 issued January 20, 1976. These materials are typicaily,
though necessarily used in fraction per- centages of the composition by weight. They
are not soluble in the remainder of the composition, but stay suspended as finely
dispersed droplets and particles, respectively. Even though compositions containing
minor amounts of these materials may not be isotropic within the narrow technical
meaning of that word, they are considered herein to be compositions within the scope
of this invention.
Processing.
[0065] The complete compositions of this invention at equilibrium, at room temperature,
are homogeneous, isotropic liquids. The components thereof, when mixed thoroughly
together in any fashion, will ultimately form this phase. It is convenient, however,
to add the components in an order and a manner that will avoid the temporary formation
of intermediate non-isotropic phases. The process described in detail hereinafter
in the preparation of Composition A, with polyol substituted for ethanol, is such
a convenient process.
INDUSTRIAL APPLICATION
[0066] The following examples describe the formulation and processing of certain compositions
of this invention and the benefits obtained therefrom as compared with certain other
compositions. They are illustrative of the invention and are not to be construed as
limiting thereof.
[0067] Composition A according to the teachings of the prior art was prepared and formulated
as follows:
a) A caustic "seat" was prepared by premixing 129.9 gm. H20, 18.4 gm. of a 48.8% solution of NaOH, 20.9 gm. of a 45% solution of KOH, 14.0 gm.
of pentasodium diethylene trtamine pentaacetic acid (43% active), and 70 gm. monoethanolamine.
b) A builder premix was prepared by mixing 50.0 gm. H20, 1.6 gm. calcium hydroxide (97% active), 46.0 gm. citric acid (anhydrous), and 6.9
gm. sodium formate.
c) A brightener premix was prepared by mixing 20.0 gm. H20, 20 gm. of ethanol (92.5% active), and 1.8 gm. brightener.
[0068] The final composition was prepared by adding the components together, with continuous
mixing, in the following order: caustic seat, builder premix, 74.7 gms. of C13 linear
alkyl benzene sulfonate (96.4% active), brightener premix, 50.3 gm. ethanol, 216.3
gm. of C
14-C
15 alkyl polyethoxy ether sulfate paste having 1.9 (avg.) -CH
2CH
20- groups per molecule (49.9% active paste
*), 150 gm. of lauric/myristic acid (1/1 wt. ratio), 65 gm. of C
12-13 alkyl
polyethoxylate having 6.5 (avg.) -CH
2CH
20- groups per molecule, and 12.5 gm. of tetraethylene pentaimine ethoxylate having
15-18 (avg.) -CH
2CH
20- groups per hydrogen site. The pH was adjusted with 20.0 gm. of NaOH (100% basis),
enzymes were added in the form of 8.2 gm. Maxatase and 1.7 gm. Termamyl, and finally
2.0 gm. perfume was added. Total batch size was 1000 gm.
* Contained 18.7% 1,2-propane diol, or 40.4 gm. and 1.5% sodium formate, or 3.2 gm.
[0069] Components were present in the following proportions, some of them being specified
on an acid basis:
[0070] Composition A was an isotropic liquid as made at room temperature (20°C). Its pH
was 8.3 when measured on a 10% solution of the composition at 20
0C. Its odor was not pleasant.
[0071] Then was prepared in the same manner a series of compositions which were like Composition
A except that in each case perfume and one or more other components were omitted and
replaced with additional water. These compositions were as follows:
[0072] All of Compositions B through G were isotropic at room temperature. All pH's were
within the range 8-9 except for Compositions B and F where pH adjustments were not
made.
[0073] A panel of experts judged the odor of the samples to be in the order listed above.
Composition B, which contained fewest ingredients that cause malodor, was best. Composition
C, which contained no ethanol, was nearly as good, even with both monoethanol amine
and enzyme present. Compositions D and E were poor, while F and G were even worse
and about equal to each other.
[0074] In Compositions D and E, the ethanol is believed to have lifted up and emphasized
the grainy/meaty malodor of the enzyme and the painty, metallic malodor of the monoethanolamine,
respectively. In Compositions F and G, the ethanol lifted up the malodors of both
the monoethanolamine and the enzyme.
[0075] Composition C is an example of this invention. Compositions A, B, D, E, F and G are
comparative examples.
[0076] Another composition, which is identified in detail hereinbefore as Composition H,
was prepared in the same manner as was Composition A except for differences in the
amounts of the various components. As noted, the components added up to less than
100 parts because it was intended that a "hole" be left in the formula for addition
of varying mixtures of additional solvents. Each of Compositions I through V that
are identified below was prepared by adding, to Composition H, amounts of 1,2-propane
diol, ethanol and/or water sufficient to make 99.8 total parts. [The 0.2 parts "hole"
left for adding perfume was never filled.] These components contained solvent mixtures
as follows:
[0077] All compositions I through V were homogeneous and isotropic as made at 20°C. and
remained so upon storage indefinitely at room temperature or up to two months' exposure
to elevated temperature (38°C). All compositions except I, J and Q, which contained
relatively low solvent levels as compared with their levels of surfactants and other
solids, recovered their isotropic character perfectly after being subjected to three
freeze/thaw cycles (4°C./20°C.). In general, the higher the level of total solvent
the lower the temperature that the compositions withstood for prolonged periods without
losing their isotropic character, with the best of them being good for 2 months at
-4°C. Ethanol was somewhat more effective than 1,2-propane diol on a part-for-part
basis.
[0078] The odor of Compositions I through N, which contained no ethanol and were Compositions
of this invention, was good. The odor of Compositions O through U, comparative examples
which contained 1.62% ethanol or more, was poor.
[0079] The detergent performance of all compositions I through V is good.
[0080] Composition W was prepared in the same manner as Compositions I through V and contained
6.5 parts ethanol plus 3.9 parts 1,2-propane diol, making a total of 10.4 parts solvent
and a solvent ratio of 5/3 expressed in the terms of the preceding table. Flash points
were measured for this composition and for Composition N, which was the same except
for solvent content. Results were as follows:
[0081] Composition N, an example of this invention, had a significantly higher, and therefore
safer, flash point than Composition W, a comparative example.